a. Field of Invention
The invention relates generally to liquid dispensers, and, more particularly, to a mechanically propelled metered dispenser for dispensing a predetermined quantity of liquid product.
b. Description of Related Art
Finger-powered dispensing pumps are known in the art, and generally include a finger operated pump head, which when depressed, discharges liquid product from a container having the pump mounted thereon. An exemplary finger-powered dispensing pump is disclosed in U.S. Pat. No. 3,414,169. Such pumps can be arranged as sprayers or atomizers in which a spray nozzle emits the pumped liquid as a spray, as shown in U.S. Pat. Nos. 3,194,447 and 4,433,799. Alternatively, the pumps can be arranged as liquid dispensers in which a dispensing nozzle thereof is a discharge spout, as shown in U.S. Pat. No. 3,216,625.
It is desirable that means be provided for metering the amount of liquid dispensed, and also that such means be easy for a consumer to operate. For example, if the pump is used on a spray dispensing bottle for a hair spray, a consumer may desire a generally repeatable amount of spray dispensed per pump actuation. However, if the pump is used with a medicine dispensing bottle, it is desirable that the dispensed amount be repeatable and precise for imparting the intended effect.
Such an exemplary metered dispenser for dispensing of medicine is disclosed in U.S. Pat. No. 5,613,957 to Py. Specifically, referring to FIG. 1 of Py, there is disclosed an apparatus (10) for applying medicament and generally including an outer body (12), an inner body (14) and a piston body (16). When piston body (16) is located in the up position (see FIG. 1), medicament is permitted to flow from medicament chamber (33), through slots (46), and drop cavity (38) to fill the drop cavity. When piston body (16) is pushed toward outer body (12) and into a down position, the downward stroke of piston (18) forces the medicament in drop cavity (38) through channel (44) and into interface (25). During this downward stroke of piston (18), flexible rim (40) is forced outwardly into contact with cylindrical wall (36), thus preventing the passage of medicament in drop cavity (38) back into medicament chamber (33). The pressurized medicament flowing through channel (44) opens interface (25) by forcing flexible outer nozzle portion (22) away from inner nozzle portion (24) to open the nozzle and release the medicament. Once the medicament is released, outer nozzle portion (22) returns to its normal position in contact with inner nozzle portion (24) so as to close interface (25).
As readily evident from the afore-described operation of the Py metered dispenser, the dispenser requires piston body (16) to be pushed toward outer body (12) for dispensing of medicine through nozzle (20). When used adjacent an eye or a nostril for dispensing medicine, such a pushing action can lead to contact of the nozzle tip with a user's eye to contaminate the dispenser, and more importantly, can present a danger to the user's eye during repeated use if the nozzle tip indeed becomes contaminated. Yet further, since the amount of medicine dispensed is a function of piston body (16) which is pushed toward outer body (12), the amount of medicine dispensed can vary depending on whether a user completely pushes piston body (16) toward outer body (12), which can also be a function of a user's ability to push piston body (16) as required.
It would therefore be of benefit to provide a metered dispenser which is repeatable in operation to dispense a predetermined dosage of medicine or other products, and which is usable by a broad range of users to repeatedly dispense a metered dosage of medicine without fluctuations in the amount of medicine dispensed. It would also be of benefit to provide a metered dispenser which is simple and economical to manufacture and assemble, and which is robust in design and efficient to operate.
The following patents are representative of metered dispensers with feed-containing piston drive mechanisms:
U.S. Pat. No. 3,754,687 to Robert W. Norton describes a pipetting dispenser of the piston-cylinder type with interchangeable fittings by which the operative movement of the piston may be arranged to be in line with or at an angle to the axis of an attached pipette and having adjustable stop means to limit travel of the piston within predetermined limits, together with means automatically retracting the piston from its discharge position to a position in engagement with said adjustable stop means, thereby insuring the repeated dispensing of the like volumes of liquid from said pipette in successive operations of the dispenser, for any adjusted position of the stop means.
U.S. Pat. No. 3,934,585 to David M. Maurice discloses a method and apparatus for applying therapeutic eye drops to the eye by metering a predetermined volume of fluid and rapidly applying a pressure to one end of the metered fluid for forcing the fluid from a nozzle of means defining a small passageway such as and open-ended tube as a droplet having sufficient velocity to travel a generally horizontal distance in space to the eye. Unit dose application and multiple dose applications are included and provision is made for preventing anticipatory blinking of the eye during self-administration.
U.S. Pat. No. 4,091,677 to Yuji Oshikubo describes a pipetting apparatus comprising a housing, a liquid receiving tube attached to the lower end of the housing and receiving a predetermined amount of a liquid sample herein, a cylinder piston device disposed in the housing for applying vacuum pressure on the upper end of the liquid receiving tube for sucking a liquid sample into the tube, a manually operable device for actuating the cylinder piston device, an air inlet for directing compressed air into the housing, and a manually operable valve for directing compressed air either to the upper end of the liquid receiving tube or to atmosphere.
U.S. Pat. No. 5,226,895 to Dale C. Harris describes a present invention which relates to a hypodermic syringe having the same general appearance as a pen which is specifically adapted to provide for multiple measured injections of materials such as insulin or human growth hormone.
U.S. Pat. No. 5,267,986 to Daniel Py describes and illustrates a cartridge for actuating a piston-like or accordion-like dispenser-vial for applying medication to any eye. The cartridge includes a housing for holding the dispenser-vial and a telescoping cylinder for compressing the dispenser-vial in the longitudinal direction to actuate the vial. The cartridge includes a locking mechanism for locking the telescoping cylinder to restrict its movement and a trigger mechanism for releasing the cylinder from the locked position so that a drop is released form the dispenser. The housing includes a finger for engaging the lower eyelid and exposing the conjunctival cul de sac.
U.S. Pat. No. 5,401,259 to Daniel Py discloses a cartridge for actuating a piston-like or accordion-like dispenser-vial for a applying medicament to an eye. The cartridge includes a housing for holding the dispenser-vial and a telescoping cylinder for compressing the dispenser-vial in the longitudinal direction to activate the vial. The cartridge includes a locking mechanism for locking the telescoping cylinder to restrict its movement and a lever mechanism for releasing the cylinder from the locked position so that a drop is released from the dispenser. The housing includes a finger for engaging the lower eyelid and exposing the conjunctival cul-de-sac.
U.S. Pat. No. 5,613,957 to Daniel Py discloses an apparatus used for applying medicament to an eye and to store the medicament in a medicament chamber. A nozzle is coupled in fluid communication with the medicament chamber and is formed by an outer nozzle portion and an inner nozzle portion received within the outer nozzle portion. A tight interface is defined between the inner nozzle portion and the outer nozzle portion and is normally in a closed position to prevent the passage of medicament through the nozzle. The interface opens in response to the flow of medicament of sufficient pressure into it to permit the passage of medicament through the nozzle for release into the eye.
U.S. Pat. No. 5,685,869 to Daniel Py describes and illustrates an apparatus used to apply medicament to an eye and to store the medicament in a medicament chamber. A nozzle is couples in fluid communication with the medicament chamber and is formed by an outer nozzle portion and an inner nozzle portion received within the outer nozzle portion. A seam is formed by the interface of the inner nozzle portion and the outer nozzle portion and is normally in a closed position to prevent the passage of medicament through the nozzle. The seam opens in response to the flow of medicament or sufficient pressure into the seam to permit the passage of medicament through the nozzle for release into the eye.
U.S. Pat. No. 6,413,246 B1 to John E. Harrold describes a present invention that relates to a metered, mechanically propelled, liquid dispenser. It has a main body cylinder having liquid and liquid advancing mechanism for advancing the liquid into a metered dosage dispensing chamber. There is a cocking mechanism which includes a lock pin, a stressed slot and rest slot. When the cocking mechanism is locked, the advancing means is moved and liquid is ready for firing from the metered dosage dispensing chamber through a dispensing orifice. The cocking mechanism is slowly rotated while holding the main body cylinder vertically and the pin is manually moved in the rest slot thereby causing a plunger to be forced by a spring to push against a stop on a trigger which advances the trigger to rapidly force the liquid out of the metered dosage dispensing chamber through the dispensing orifice. The dispensing orifice includes a one-way valve which allows the liquid to be dispensed while preventing air from returning to the device.
U.S. Pat. No. 6,419,663 B2 to John E. Harrold describes a present invention mechanically propelled, liquid metered dispenser includes a main housing with liquid storage and a liquid advancing component for either allowing liquid to flow out or assisting in the flow of liquid out of the main housing by exerting pressure, into a metered dosage dispensing chamber in response to a loading movement of a cocking mechanism. The chamber has an inlet connected to the main housing with a one-way valve to only permit flow of liquid into the chamber. The chamber also has an outlet orifice for dispensing liquid therefrom in a metered amount. The chamber ahs a reciprocal plunger and has a load and release component connected to it, which includes a cocking mechanism, a locking mechanism, and a spring. The cocking mechanism is functionally connected to the plunger so as to move in harmony therewith, or, more preferably, to move a relatively, short distance relative to the distance traveled by the cocking mechanism.
Notwithstanding the prior art, the present invention is neither taught nor rendered obvious thereby.